1. Field of the Invention
The present invention relates to a power conditioner for a solar power generation system. Specifically, the present invention relates to a power conditioner for a solar power generation system that converts direct-current or DC power generated by a solar battery into alternating-current or AC power which is in turn interconnected with a commercial or utility power supply.
2. Description of the Background Art
In general, a power conditioner for a solar power generation system includes an inverter unit as a main circuit, an inverter driver unit, a controller unit, a display unit, an operation unit, and a power supply circuit unit which provides required power to each of these units. The display unit provides respective indications of instantaneous output power and integral power of the power conditioner that are detected and calculated by the controller unit, or an indication of a period power amount which can arbitrarily be initialized by a user. If the display unit indicates an amount of power in a certain period of time, for example, in a day or month, the display unit should have clock and calendar functions to determine the hour and (period of) time by means of a timer included therein. If the power supply circuit converts power provided from a solar battery to supply the converted power to each circuit unit, another power supply circuit is included that provides power from a nighttime timer-backup power supply or utility power supply.
According to a conventional method disclosed in Japanese Patent Laying-Open No. 2000-304779, a timer is used to calculate an amount of power in a day and indicate the calculated amount without clock function being used. For a nighttime operation, a power supply circuit is used that supplies power from a nighttime backup power supply or utility power supply, in order to provide only stored indications according to any manipulation. Here, data is not updated for example.
The solar power generation system is employed for the purpose of predominantly utilizing power generated by means of a solar battery and thus reducing consumption of power from the utility power supply. If the generated power exceeds household power consumption, the surplus power may inversely be flown and sold to an electric power utility company. Thus, the amount of generated power serves as important information for users or customers.
The amount of power generated by a solar battery varies depending on the amount of solar radiation and thus a constant output power is impossible to produce. For this reason, it is difficult to estimate the amount of power based on time. It is thus advantageous functionally to enable users or customers to ascertain the amount of generated power as well as the transition of the amount of power.
According to the conventional method without clock function, in order to know a daily amount of generated power, it is necessary to read an indication of an integral power amount and subtract the power amount every day or to initialize a period power amount every day, which is troublesome.
According to the conventional method with clock function, it is possible to automatically calculate and display an amount of power generated in a day. However, accurate information cannot be given if the time is incorrect, therefore, the time must be set upon installation. In addition, if the utility power supply is used as an internal power supply and an electric power failure or outage occurs, the time must be set again after recovery from the power failure. If the timer uses a battery as a power source, troublesome battery replacement and time setting are required when the battery becomes exhausted.
In addition, according to the conventional method by which time is measured not by means of clock function but timer for calculating and displaying an amount of power, one day means a time period from the time preceding by 24 hours to the present time. Thus, the amount of power does not represent an amount of power generated in a period from the start of power generation of the instant day, but represents an amount of power generated in 24 hours. In other words, if an amount of power generated in one day is ascertained at noon, the amount of power represents the one generated in a period from the yesterday noon to the present time (noon). Then, it is impossible to know the amount of power generated in a period from the start of power generation of the instant day to the noon of that day.
Moreover, if the power supply circuit converts power from a solar battery and supplies the converted power to each circuit, the control circuit unit of the power conditioner does not operate in the nighttime during which no power is generated by the solar battery. Then, any manipulation of a remote controller in the nighttime is not accepted, or manipulation details in the nighttime are not reflected and accordingly become invalid.
One object of the present invention is thus to provide a power conditioner for a solar power generation system that can display information concerning power generation, for example, an amount of power solar-generated in a day, without clock function and without requiring hour- or time-setting.
Briefly, the present invention is a power conditioner for a solar power generation system that has an inverter converting power generated by a solar battery into AC power to interconnect the AC power with a utility power supply. The power conditioner includes a control circuit which has a memory storing data for one day. The control circuit manages a time during which the inverter stops, and determines that one day has passed when the time is equal to or longer than a predetermined time. Then, the control circuit clears the memory and stores new data in the memory.
According to the present invention, it is thus possible to ascertain daily information of the power conditioner, without internal clock function and without troublesome time-setting.
The power conditioner further includes a display unit for displaying an amount of power generated in a predetermined time when the inverter operates. The amount of power is represented by a certain number of graphs. The control circuit updates data displayed by the display unit as time passes, successively moves previous data on the graphs, and maintains the displayed data as it is without updating the displayed data during a time in which the inverter stops.
The power conditioner further includes a remote controller separated from the control circuit for remotely providing a control command to the control circuit.
The remote controller operates by receiving power from the utility power supply to manage the time during which the inverter stops.
The remote controller operates by receiving power from the solar battery when the inverter is running, and transmits, to the control circuit, details of manipulation of the remote controller when the inverter stops, the details of manipulation being transmitted when the inverter is started.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.